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Detection of heavy metals have been pivotal due to their non-biodegradability and food chain accumulation. Herein, a multivariate ratiometric sensor was developed by in situ integrating AuAg nanoclusters (NCs) into electrospun cellulose acetate nanofibrous membranes (AuAg-ENM) for visual detection of Hg 2+ , Cu 2+ and consecutive sensing of l-histidine (His), which was integrated into a smartphone platform for quantitative on-site detection. AuAg-ENM achieved multivariate detection of Hg 2+ and Cu 2+ by fluorescence quenching, and subsequent selective recovery of the Cu 2+ -quenched fluorescence by His, which distinguished Hg 2+ and Cu 2+ and fulfilled determination of His simultaneously. Notably, AuAg-ENM achieved selective monitoring of Hg 2+ , Cu 2+ and His in water, food and serum samples with high accuracy comparable to ICP and HPLC tests. A logic gate circuit was devised to further explain and promote the application of AuAg-ENM detection by smartphone App. This portable AuAg-ENM provides a promising reference for fabricating intelligent visual sensors for multiple detection., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

A dual-mode colorimetric and fluorimetric probe was successfully established based on silver/copper bimetallic nanoparticles (AgCu-BNPs). The AgCu-BNPs were confirmed as individually bimetallic nanoparticles with a mean size of 7.7 ± 0.2 nm, as characterized by high resolution transmission electron microscopy. Intriguingly, the AgCu-BNPs possess both surface plasmon resonances (SPR) and fluorescence emission. AgCu-BNPs emanate bright blue fluorescence with optical emission centered at 442 nm with high quantum yield of 30.3%, and AgCu-BNPs were attenuated or even quenched by Hg 2+ via both static and dynamic quenching, coincidently accompanied by a visible color change, which endow AgCu-BNPs a unique utility as dual-mode colorimetric and fluorimetric probes. The detection limits as low as 89 nM and 9 nM were determined by dual-mode of AgCu-BNPs, respectively. The recovery rates in real samples were found to be 97.3-118.8%, and 89.5-112.7% by colorimetric and fluorescent methods separately, demonstrates the good environmental tolerance of the dual-mode probe., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Mercury (Hg) is the most toxic heavy metal and can lead to severe irreversible injury to human health and serious pollution. It is of great significance to explore precise and facile detection methods for preventing environmental pollution and ecological problems. Herein, silicon-doped carbon dots (Si-CDs) with bright blue emission were fabricated and employed as a fluorescent probe for the quantitative detection of Hg2+. Possessing high photostability and excellent solubility in water, the Si-CDs exhibit an efficient response to Hg2+ by a "on–off" switching strategy. As a sensing probe, Si-CDs exhibit a good linear relationship with Hg2+ in the concentration range of 0.008–0.4 μM with a limit of detection of 33 nM. Moreover, the proposed method was successfully applied to monitor Hg2+ in different real water samples with satisfactory recoveries of 96.2%–99.5%, demonstrating their excellent accuracy and environment tolerance. Notably, the Si-CD powder obtained by lyophilization can visualize latent fingerprints with second-level details. The results serve to underscore how CDs designed for multiple applications in detection can be exploited to provide promising multi-functional fluorescent materials. [ABSTRACT FROM AUTHOR]

As the most toxic heavy metal, mercury (Hg) has been considered as the greatest environmental threat and it reach ubiquitous in industrial waste water and extended to environment. The detection of Hg2+ in environmental water is a crucial work for both protecting the environment and human health. Colorimetric assay exhibits visual discriminating and simple readout. This work presents the selective sensing of metal ion (Hg2+) by silver particles (Ag NPs), which were functionalized by galactosamine and synthesized via simple one pot method, with the average particle diameter of 18.75±0.49 nm. The limit of detection (LOD) was calculated as low as 7.92 nM. The colorimetric probe can also be performed in real water sample with good selectivity, and recovery was found to be 95–102 %, indicating can be used for on‐line determination of Hg2+ in the complex aqueous solutions. Additionally, the good catalytic performance of Ag NPs was demonstrated by hydrogenation of p‐nitrophenol and potassium ferricyanide in water samples. [ABSTRACT FROM AUTHOR]